One prior modem device modulates digital computer signals into analog signals for transmission on a Public Switched Telephone Network (PSTN) telecommunications system and demodulates analog transmission signals received from a PSTN telecommunications system into digital computer signals.
However, the prior modem devices cannot transmit or receive signals over a cellular telecommunications system; because, the cellular system utilizes signals of a different format than the PSTN system. Thus, when using the prior modem device with a portable computer, the user is limited to areas with access to a PSTN telecommunications system. This limitation restricts the portability of portable computer systems. In addition, because the prior modem device can only operate on one type of telecommunications system (i.e. a PSTN system), the user does not face the previously unrecognized problem of selecting a mode for a telecommunications system and performing the necessary configuration steps to switch to the selected mode. This problem, which occurs on a modem device that can operate on more than one type of telecommunications system, greatly reduces the convenience and ease of using a modem device.
Thus, a modem device capable of transmitting and receiving telecommunications signals in a plurality of operational modes is needed.
What is also needed is a modem device capable of automatically selecting between a plurality of operational modes.